Dysarthria happens when the muscles used for speech are weak or are hard to control. Dysarthria often causes slurred or slow speech that can be difficult to understand.

Common causes of dysarthria include conditions that affect the nervous system or that cause facial paralysis. These conditions may cause tongue or throat muscle weakness. Certain medicines also can cause dysarthria.

Treating the underlying cause of dysarthria may improve your speech. You also may need speech therapy. For dysarthria caused by prescription medicines, changing or stopping the medicines may help.

Symptoms of dysarthria depend on the underlying cause and the type of dysarthria.

Symptoms may include:

• Slurred speech.
• Slow speech.
• Not being able to speak louder than a whisper or speaking too loudly.
• Rapid speech that is difficult to understand.
• Nasal, raspy or strained voice.
• Uneven speech rhythm.
• Uneven speech volume.
• Monotone speech.
• Trouble moving your tongue or facial muscles.

When to see a doctor

Dysarthria can be a sign of a serious condition. See a healthcare professional right away if you have sudden or unexplained changes in your ability to speak.

Dysarthria can be caused by conditions that make it hard to move the muscles in the mouth, face or upper respiratory system. These muscles control speech.

Conditions that may lead to dysarthria include:

• Amyotrophic lateral sclerosis, also known as ALS or Lou Gehrig's disease.
• Brain injury.
• Brain tumor.
• Cerebral palsy.
• Guillain-Barre syndrome.
• Head injury.
• Huntington's disease.
• Lyme disease.
• Multiple sclerosis.
• Muscular dystrophy.
• Myasthenia gravis.
• Parkinson's disease.
• Stroke.
• Wilson's disease.

Some medicines also can cause dysarthria. These may include certain sedatives and seizure medicines.

Dysarthria risk factors include having a neurological condition that affects the muscles that control speech.

Complications of dysarthria may come from having trouble with communication. Complications may include:

• Trouble socializing. Communication problems may affect your relationships with family and friends. These problems also may make social situations challenging.
• Depression. In some people, dysarthria may lead to social isolation and depression.

To diagnose dysarthria, a speech-language pathologist might evaluate your speech to help find out the type of dysarthria you have. This can be helpful to the neurologist, who will look for the underlying cause.

During the speech evaluation, the speech-language pathologist listens carefully to your speech and identifies features of dysarthria. You may be asked to read aloud and repeat words and phrases. The speech-language pathologist also evaluates your ability to move and control the muscles of your face, tongue and throat.

Your healthcare professional also might order tests to look for underlying conditions, including:

• Imaging tests. Imaging tests create pictures of the body. For dysarthria, tests such as an MRI or CT scan may be used to create detailed images of your brain, head and neck. These images may help find the cause of your speech problem.
• Brain and nerve studies. Brain and nerve studies can help pinpoint the source of your symptoms. An electroencephalogram, also known as EEG, measures electrical activity in your brain. An electromyogram, also known as EMG, evaluates electrical activity in your nerves as they transmit messages to your muscles. Nerve conduction studies measure the strength and speed of the electrical signals as they travel through your nerves to your muscles.
• Blood and urine tests. Blood and urine tests can help find out if an infectious or inflammatory disease is causing your symptoms.
• Lumbar puncture. A lumbar puncture, also known as a spinal tap, is used to collect a small sample of cerebrospinal fluid for testing in a lab. During this procedure, a healthcare professional inserts a needle into your lower back to remove the sample. A lumbar puncture can help diagnose serious infections, disorders of the central nervous system, and cancers of the brain or spinal cord.
• Brain biopsy. If a brain tumor is suspected, your healthcare professional may remove a small sample of your brain tissue for testing in a lab.
• Neuropsychological tests. Neuropsychological tests measure your thinking skills and your ability to understand speech, reading, and writing. Dysarthria doesn't affect these skills, but an underlying condition can.

Treatment for dysarthria depends on the cause and severity of your symptoms. Treatment also may depend on the type of dysarthria you have.

When possible, the underlying cause of your dysarthria is treated. This may help improve your speech. If your dysarthria is caused by prescription medicines, talk to your healthcare professional about changing or stopping these medicines.

Speech and language therapy

You may have speech and language therapy to help you regain speech and improve communication. Your speech therapy goals might include adjusting speech rate, strengthening muscles, increasing breath support, improving articulation and helping family members communicate with you.

Your speech-language pathologist may recommend trying other communication methods if speech and language therapy isn't effective. These communication methods could include visual cues, gestures, an alphabet board or computer-based technology.

If dysarthria makes your speech hard to understand, these suggestions may help you communicate more effectively:

• Get the listener's attention. Call the listener's name or otherwise get their attention before speaking. It helps when you and the listener can see each other's faces before you start talking.
• Speak slowly. Listeners may understand you better when they have more time to think about what they're hearing.
• Start small. Introduce your topic with one word or a short phrase before speaking in longer sentences.
• Gauge understanding. Ask listeners to confirm that they know what you're saying.
• If you're tired, keep it short. Fatigue can make your speech harder to understand.
• Have a backup. Writing messages can be helpful. Type messages on a cellphone or hand-held device. Consider carrying a pencil and small pad of paper with you.
• Use shortcuts. Create drawings and diagrams or use photos during conversations. This way you don't have to say everything. Gesturing or pointing to an object also can help convey your message.

Family and friends

If you have a family member or friend with dysarthria, the following suggestions may help you better communicate with that person:

• Reduce distracting noises in the environment.
• Allow the person time to talk.
• Look at the person when they are speaking.
• Don't finish their sentences or correct errors.
• If you don't fully understand what the speaker said, avoid asking "What?" Instead, repeat back the words you heard and understood so the speaker only has to repeat the unclear parts of the message.
• Ask yes or no questions.
• Keep paper and pencils or pens readily available.
• Help the person with dysarthria create a book of words, pictures and photos to help with conversations.
• Involve the person with dysarthria in conversations as much as possible.
• Talk regularly. Many people with dysarthria understand others. There's no need to slow down or speak loudly when you talk.

Dysarthria requires prompt medical attention. See a doctor or other healthcare professional right away if you have sudden or unexplained changes in your ability to speak.

If the changes are more subtle, you'll likely start by seeing your primary care doctor. If your doctor suspects that a medical condition is causing your symptoms, you will likely be referred to a nervous system specialist, called a neurologist, for further evaluation.

What you can do to prepare

• Be aware of pre-appointment restrictions. Ask if there's anything you need to do in advance, such as restrict your diet for blood tests.
• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Write down important personal information, including any major stresses or recent life changes.
• Make a list of all medicines, vitamins or supplements that you're taking.
• Consider taking a family member or friend along. Sometimes it can be hard to absorb all the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot.
• Write down questions to ask your healthcare professional.

Questions to ask your doctor

Your time with your healthcare professional is limited. Prepare a list of questions so that you can make the most of your time together. List your questions from most important to least important in case time runs out. For dysarthria, some basic questions to ask include:

• What's the most likely cause of my symptoms?
• What tests do I need?
• Will I need to see a specialist?
• What treatments are available?
• Are there brochures or other printed material that I can have? What websites do you recommend?

Don't hesitate to ask other questions, as well.

What to expect from your doctor

Be prepared to answer some questions about your symptoms and your health, such as:

• When did you first begin experiencing symptoms?
• Have your symptoms been ongoing or occasional?
• How severe are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?